DEF LEPPARD and JOURNEY will be teaming up for a U.S. tour this summer. No dates have been confirmed at this time.DEF LEPPARD's two-CD collection of hits, "Rock of Ages", has sold 452,000 copies in the United States since its May 2005 release. Meanwhile, the band's 1999 "Vault - Greatest Hits" (Mercury) collection has shifted 4.08 million copies so far. DEF LEPPARD's all-covers set, entitled "Yeah!", is tentatively scheduled for release in May. Guitarist Phil Collen told Billboard.com last year that the album will include "a bunch of stuff — all '70s stuff. Most of it is songs that we grew up with in England. 'No Matter What' by BADFINGER is going to be the leadoff single. We've done 'Waterloo Sunset' by THE KINKS, T. REX, MOTT THE HOOPLE, ROXY MUSIC and THIN LIZZY. And a lot of it is obscure; it's not the standard stuff. It's not like STONES or BEATLES songs."